This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Coxiella burnetii is an obligate intracellular bacterium that causes Q fever in humans. Prolonged passage of this microorganism in tissue culture cells bypasses the normal in vivo exposure to the host immune system and leads to some clones with altered virulence and lipopolysaccharide (LPS) profiles. Two of these independently derived clones had previously been characterized with a loss of 20-30 kilobases (kb). The two deletions in question partially overlap. With respect to the wild type, one of the deletion strains is avirulent and has a LPS with a much reduced molecular weight. The other strain is fully virulent and has a LPS with an intermediate molecular weight. A 38 kb stretch of DNA that corresponds to the deleted areas has recently been sequenced from the wild type strain, and primers have been designed to verify the four deletion termini. A list of open reading frames has been compiled from the sequence data. Some of these have been assigned functions based on their similarity to motifs and/or proteins in databases, while the function of others remains elusive. The absence of a particular LPS biosynthetic gene does correlate with the more extreme LPS chemotype. Another project involves the surveillance of mosquito pools with RT-PCR assays for arbovirus carriage. These viruses are responsible for episodic outbreaks of human encephalitides in the US. The surveillance is done for a practical consideration so that mosquito control can be specifically targeted for time and location. From a theoretical perspective, it allows us to search for enzootic foci and to assess which climatological and biological parameters are associated with these outbreaks. Publications - Reno, H.E., Vodkin, M.H., and Novak, R.J.: "Differentiation of Aedes triseriatus (Say) from Aedes hendersoni Cockerell (Diptera: Culicidae) by restriction fragment length polymorphisms of amplified ribosomal DNA." American J. Tropical Med. &Hyg.: 62:193-199: 2000.